Cleanup the rb_catch_obj workaround

Followup: #1031

Now that the bug has been fixed upstream, we can only apply
it on unpatched version.

Also refactor the workaround to expose the exact same API
as `rb_catch_obj`, making it easier to ignore and remove later.

Author: byroot

ext/json/ext/json.h

@@ -144,4 +144,36 @@ static inline void *ruby_xrealloc2_sized(void *ptr, size_t new_elems, size_t ele
 #define JSON_CPU_LITTLE_ENDIAN_64BITS 0
 #endif
 
+#ifdef JSON_TRUFFLERUBY_RB_CATCH_BUG
+
+#undef RB_BLOCK_CALL_FUNC_ARGLIST
+#define RB_BLOCK_CALL_FUNC_ARGLIST(yielded_arg, func_args) VALUE func_args
+
+NORETURN(static inline) void json_rb_throw_obj(VALUE tag, VALUE obj)
+{
+    VALUE exc = rb_exc_new_str(rb_eException, rb_utf8_str_new_cstr("throw_workaround"));
+    rb_ivar_set(exc, rb_intern("@throw_tag"), tag);
+    rb_ivar_set(exc, rb_intern("@throw_obj"), obj);
+    rb_exc_raise(exc);
+}
+#define rb_throw_obj json_rb_throw_obj
+
+static inline VALUE json_rb_catch_obj(VALUE tag, VALUE (*func)(VALUE args), VALUE func_args)
+{
+    int status;
+    VALUE result = rb_protect(func, func_args, &status);
+    if (status) {
+        VALUE exc = rb_errinfo();
+        if (tag == rb_ivar_get(exc, rb_intern("@throw_tag"))) {
+            rb_set_errinfo(Qnil);
+            return rb_ivar_get(exc, rb_intern("@throw_obj"));
+        }
+        rb_jump_tag(status);
+    }
+    return result;
+}
+#define rb_catch_obj json_rb_catch_obj
+
+#endif // JSON_TRUFFLERUBY_RB_CATCH_BUG
+
 #endif // _JSON_H_

ext/json/ext/parser/extconf.rb

@@ -2,7 +2,12 @@
 require 'mkmf'
 
 $defs << "-DJSON_DEBUG" if ENV.fetch("JSON_DEBUG", "0") != "0"
-$defs << "-DJSON_WORKAROUND_RB_CATCH_BUG" if RUBY_ENGINE == 'truffleruby'
+
+if RUBY_ENGINE == 'truffleruby' && RUBY_VERSION < '4.0'
+  # Ref: https://github.com/truffleruby/truffleruby/issues/4329
+  # Ref: https://github.com/truffleruby/truffleruby/pull/4333
+  $defs << "-DJSON_TRUFFLERUBY_RB_CATCH_BUG"
+end
 
 have_func("rb_enc_interned_str", "ruby/encoding.h") # RUBY_VERSION >= 3.0
 have_func("rb_str_to_interned_str", "ruby.h") # RUBY_VERSION >= 3.0

ext/json/ext/parser/parser.c

@@ -672,43 +672,13 @@ static VALUE parse_error_new(JSON_ParserState *state, VALUE message, long line,
     return exc;
 }
 
-#ifdef JSON_WORKAROUND_RB_CATCH_BUG
-#define JSON_CATCH_FUNC_ARGLIST(yielded_arg, func_args) VALUE func_args
-
-NORETURN(static) void parser_throw_eos(VALUE parser)
-{
-    VALUE exc = rb_exc_new_str(eParserError, rb_utf8_str_new_cstr("EOS"));
-    rb_ivar_set(exc, rb_intern("@resumable_parser_eos"), parser);
-    rb_exc_raise(exc);
-}
-
-static VALUE parser_catch_eos(VALUE parser, VALUE (*func)(VALUE args), VALUE func_args)
-{
-    int status;
-    VALUE result = rb_protect(func, func_args, &status);
-    if (status) {
-        VALUE error_source = rb_ivar_get(rb_errinfo(), rb_intern("@resumable_parser_eos"));
-        if (error_source == parser) {
-            rb_set_errinfo(Qnil);
-            return parser;
-        }
-        rb_jump_tag(status);
-    }
-    return result;
-}
-#else
-#define JSON_CATCH_FUNC_ARGLIST RB_BLOCK_CALL_FUNC_ARGLIST
-#define parser_throw_eos(parser) rb_throw_obj(parser, parser)
-#define parser_catch_eos(parser, func, func_args) rb_catch_obj(parser, func, func_args)
-#endif
-
 NORETURN(static) void raise_parse_error(const char *format, JSON_ParserState *state, bool eos)
 {
     if (state->parser) { 
         if (eos) {
             // the error will be swallowed by ResumableParser#parse, so no
             // point building a message or backtrace.
-            parser_throw_eos(state->parser);
+            rb_throw_obj(state->parser, state->parser);
         } else {
             // line and columns can't be accurate in resumable
             rb_exc_raise(parse_error_new(state, build_parse_error_message(format, state), 0, 0, eos));
@@ -2450,7 +2420,7 @@ struct json_parse_any_args {
     VALUE parser;
 };
 
-static VALUE json_parse_any_resumable_safe0(JSON_CATCH_FUNC_ARGLIST(yielded_arg, _args))
+static VALUE json_parse_any_resumable_safe0(RB_BLOCK_CALL_FUNC_ARGLIST(yielded_arg, _args))
 {
     struct json_parse_any_args *args = (struct json_parse_any_args *)_args;
     return (VALUE)json_parse_any(args->state, args->config, true);
@@ -2459,7 +2429,7 @@ static VALUE json_parse_any_resumable_safe0(JSON_CATCH_FUNC_ARGLIST(yielded_arg,
 static VALUE json_parse_any_resumable_safe(VALUE _args)
 {
     struct json_parse_any_args *args = (struct json_parse_any_args *)_args;
-    VALUE result = parser_catch_eos(args->parser, json_parse_any_resumable_safe0, _args);
+    VALUE result = rb_catch_obj(args->parser, json_parse_any_resumable_safe0, _args);
     return result == args->parser ? Qfalse : result;
 }